Which one has greater dynamic range, CD or LP?

Discussion in 'Sound Science' started by Pete-FIN, Oct 20, 2017.
  1. Pete-FIN
    Purpose of this thread and my title question are purely theoretical. I hope people keep this premise in their mind, if and when this thread starts to have opinionated comments favoring or bashing either one of the formats.

    Feel free to tell your opinion about CD or LP, even though the purpose of this thread is to find an answer to my theoretical question.

    The answer I'm primarily looking for is just a number. A number indicating the maximum, widest possible, dB range. The dB range between noise floor and loudest possible sound that can be recorded.

    But of course, making a recording in a studio is very complicated process, so if you provide the numeral answer I'm looking for, it would be very nice if you could give some explanation in what kind of circumstances your given answer can be achieved.

    I'm hoping some one working in the recording industry could provide verified answers, but if anyone else has the answers that I'm looking for, then of course, feel free to tell. But, if you are not a professional, it would be nice if you could tell where you got your information from.

    So, my questions.

    Which one has greater dynamic range, CD or LP?
    How big is the theoretical maximum dynamic range on CD, and how big is it on LP?
     
  2. Mr Rick
    CDs have the capability of reproducing greater dynamic range then an LP. But dynamic range is primarily a function of the recording process.

    So, your question really has no definitive answer.
     
  3. Niouke
    hey wake up we have a client! :zzz:
     
    Last edited: Oct 20, 2017
  4. Muinarc
    Wikipedia has your answer, I googled it for you. https://en.wikipedia.org/wiki/Dynamic_range

    "Digital audio with undithered 20-bit digitization is theoretically capable of 120 dB dynamic range. 24-bit digital audio calculates to 144 dB dynamic range. [9] Most Digital audio workstations process audio with 32-bit floating-point representation which affords even higher dynamic range and so loss of dynamic range is no longer a concern in terms of digital audio processing. Low dynamic range audio mixes typically result from improper gain staging, imperfections in the analog-to-digital and digital-to-analog conversions, recording technique including ambient noise and intentional application of dynamic range compression.

    Dynamic range in analog audio is the difference between low-level thermal noise in the electronic circuitry and high-level signal saturation resulting in increased distortion and, if pushed higher,
    clipping.[23] Multiple noise processes determine the noise floor of a system. Noise can be picked up from microphone self-noise, preamp noise, wiring and interconnection noise, media noise, etc.

    Early 78 rpm phonograph discs had a dynamic range of up to 40 dB,
    [24] soon reduced to 30 dB and worse due to wear from repeated play. Vinyl microgroove phonograph records typically yield 55-65 dB, though the first play of the higher-fidelity outer rings can achieve a dynamic range of 70 dB.[25]

    German magnetic tape in 1941 was reported to have had a dynamic range of 60 dB,
    [26] though modern day restoration experts of such tapes note 45-50 dB as the observed dynamic range.[27] Ampex tape recorders in the 1950s achieved 60 dB in practical usage,[26] though tape formulations such as Scotch 111 boasted 68 dB dynamic range.[28] In the 1960s, improvements in tape formulation processes resulted in 7 dB greater range,[28] and Ray Dolby developed the Dolby A-Type noise reduction system that increased low- and mid-frequency dynamic range on magnetic tape by 10 dB, and high-frequency by 15 dB, using companding (compression and expansion) of four frequency bands.[29] The peak of professional analog magnetic recording tape technology reached 90 dB dynamic range in the midband frequencies at 3% distortion, or about 80 dB in practical broadband applications.[28] The Dolby SR noise reduction system gave a 20 dB further increased range resulting in 110 dB in the midband frequencies at 3% distortion.[30] Compact Cassette tape performance ranges from 50 to 56 dB depending on tape formulation, with Metal Type IV tapes giving the greatest dynamic range, and systems such as XDR, dbx and Dolby noise reduction system increasing it further. Specialized bias and record head improvements by Nakamichi and Tandberg combined with Dolby C noise reduction yielded 72 dB dynamic range for the cassette.

    The rugged elements of
    moving-coil microphones can have a dynamic range of up to 140 dB (at increased distortion), while condenser microphones are limited by the overloading of their associated electronic circuitry.[31] Practical considerations of acceptable distortion levels in microphones combined with typical practices in a recording studio result in a useful operating range of 125 dB.[32]

    In 1981, researchers at Ampex determined that a dynamic range of 118 dB on a dithered digital audio stream was necessary for subjective noise-free playback of music in quiet listening environments.
    [33]

    Since the early 1990s, it has been recommended by several authorities, including the
    Audio Engineering Society, that measurements of dynamic range be made with an audio signal present, which is then filtered out to get the noise floor.[34] This avoids questionable measurements based on the use of blank media, or muting circuits."
     
    Last edited: Oct 20, 2017
  5. bigshot
    CD outperforms LP on every aspect of sound fidelity.
     
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  6. Pete-FIN
    As far as we can trust wikipedia as reliable source, then I guess we can come to a conclusion that LP's dynamic range can reach maximum up to 70 dB.

    But, the first part of Muinarcs red highlighted quote goes beyond my understanding. The quote tells 20 and 24-bit dynamic range info. CD is 16-bit. I dont understand how the provided quote really answers my quostion about CD's maximum dynamic range.

    I'm still wondering about the CD and it would be super interesting to hear studio professionals insider info about it. For example, how are large symphony orchestras captured by microphones, how large dynamic range comes to tape or computer, and when it comes time to transfer that recording to CD, then what is the theoretical or practical maximum for dynamic range.


    And what the h*** is "undithered digitization"?
     
  7. Muinarc
  8. bigshot
    Only for the first dozen seconds or so. That range drops fast as the needle moves towards the center of the record. By then, you'd be lucky to get 30-35 dB. If you think about the size of the record at the outside groove, it travels one revolution in the same time it travels the much smaller center groove. That's more groove walls to provide definition to the music and a faster ride through the groove for the needle, allowing for more volume. By the time a record hits the center groove, the distortion rises a lot, and the music has to be much more dynamically compressed. That's why the hit song was always the first song on side 2- they were allowing it a little extra bandwidth to sound better. With records where sound quality was at a premium (like classical) often had shorter side lengths- under 20 minutes to sound decent at all.

    LPs handle dynamics a little differently than CDs do. With an LP, you could increase the size and depth of the groove to make it louder- essentially expanding the peaks above the zero line. This made up for the fact that LPs had a very high noise floor. CDs have dynamics that extend downward. You can't "burn in" peaks like you can with the outer grooves of an LP, but you have a MUCH lower noise floor, so it comes out better anyway. There's a lot more headroom with normalized CDs.

    In practice, the dynamic range of the best mastered and manufactured LPs is between 45 and 50 dB. That is OK though, because the most dynamic recorded music has about that much dynamic range too. Very few CDs have much beyond that, even bombastic orchestral records. They wouldn't be comfortable to listen to with wider dynamics. You'd keep having to turn the sound up to hear the quiet parts and turn it down to keep your ears from ringing at the crescendos. More isn't necessarily better. Good engineering is about achieving balances, not focusing on the extremes.
     
    Last edited: Oct 20, 2017
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  9. Pete-FIN
    Perceived dynamic range? As, how humans experience it? Strange way of thinking dynamics. I always taught you measure sound levels with proper devices.

    I googled CD dynamic range, and found some people arguing that the known 96 dB of maximum dynamic range would not be possible, for one way or another. So I don't know if I should trust this figure of 96 dB.

    If 96 dB is the theoretical, then it would be nice to know what is the maximum in practice, if it differs from 96.
     
  10. Pete-FIN
    I'm sure this is how it would go with extreme recording. But, as I said in the very beginning, my interest in this subject is theoretical.
     
  11. Don Hills
    If your interest is the theoretical, then 96 dB is the range for CD and it is easily attainable in practice. The variation in dB values comes from the way it is measured. If you measure "all the noise at once", that is you measure the level of all the noise between 20 Hz to 20 KHz at the same time, you get 96 dB. But if you measure the noise of only part of the bandwidth, say from 1000 Hz to 1100 Hz, you get a much lower reading.
    The noise shaping referred to earlier makes use of this characteristic. Imagine the noise as being air in a balloon. There is a fixed quantity of it, and it is spread out evenly throughout the balloon. If you shape it (squeeze it) in one place, it will bulge out in another. Noise shaping moves noise from the lower frequencies where our ears are most sensitive, to higher frequencies where we don't hear so well.
     
  12. ev13wt
    Op, do you understand that 60dBa is the equivalent difference between a whole darn lot?

    If you listen to quiet passages in your room at, lets say "quiet talking" around 60 dB, and add a sudden rock concert, very loud club burst of 120dB, no wait...

    120 is a bit to much :)



    Ok, other way around. You are watching a movie and the system is averaging at a very nice "i can feel it" 85dBa when music plays. a sound -60 dB, that is around 25dB.
    25dB is a campground. At night. In winter. No wind. In a thick forest.
    Maybe you bedroom at 0400, but probably not.

    Really? What should music have as dynamic range so it can be enjoyed?

    I taken from this that both formats are ok in the dynamic range area. Other things are a different thread.


    Tl;dr: add 90dB to your room, which is 50dB average. You die from sound death.
     
    Last edited: Oct 20, 2017
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  13. bigshot
    Then averaging the dynamic range of LPs across the entire album side, you probably have a dynamic range of about 35-40 dB. That would be assuming decent vinyl and a good pressing.
     
    Last edited: Oct 21, 2017
  14. gregorio
    1. There's no one way fixed way of recording a large symph orch, it depends on the piece/s, where it's being recorded, the symph orch in question, the conductor and what it's being recorded for. Generally though, there will be an overhead array of 3 or more mics (say a Decca Tree), some spot mics for individual instruments or groups of instruments, maybe some room mics. The dynamic range recorded obviously depends on which of those mics we're taking about, the room mics will record the lowest dynamic range and the spot mics the highest (depending on what they're spot mic'ing of course). At the conductor's position measured dynamic range could be 70dB or so but in the ideal audience position it's more likely to max out at around 50dB. These are rather vague approximations because it depends on the piece, the orch, etc. You could, maybe, add 10dB to those two figures in very exceptional circumstances.
    1a. The theoretical perceivable dynamic range of CD is around 120dB when using standard noise-shaped dither, which is at least 100 times more dynamic range than even the best, most pristine LP. Not that it greatly matters though, because we'd never use all that 120dB of dynamic range as it's way more than an orch could even produce in the first place. In addition, we've got to think about listening comfort for those buying the recordings and that results in virtually no commercial recordings exceeding 60dB of dynamic range and even with a large symph orch, most would be more like 50dB or so. In practice, even a 50dB dynamic range is still pushing it for LP, which is one of the reasons why classical music recording and mixing were the early adopters of digital, with labels such a Deutsche Grammophon switching to "DDD" long before the popular music labels.

    2. There's really no such thing in practice, all digital recordings are dithered. The problem is, that for the last 20 years or so it's been standard practice to apply noise-shaped dither during the mastering phase and this significantly increases the perceived dynamic range (of the medium, CD) by moving the dither noise away from where the ear is most sensitive. However, there's no accurate measurement of dynamic range using with dither (and even less so with noise shaped dither) because it relies on perception. For this reason, if we want to quote an exact figure, the only sensible way to do that is by using the theoretical "undithered digitisation", in which case it's about 96dB.

    As a pro recording/sound engineer (with significant familiarity with symph orchs), because the CD out performs the LP in every way as far as fidelity is concerned (inc. dynamic range), it's a no-brainer.

    G
     
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  15. Pete-FIN
    Once again, thank you very much for everyone for contributing to this thread. Very happy to learn more :)

    Here (https://www.stereophile.com/content/classical-recording-hugeextreme-dynamic-range-1) you can find a list of classical CD's that have large dynamic range.

    Interesting. I guess under 50 dB, is in practice the maximum dynamic range that is actually put to CD, or LP.

    96 dB it is. Case closed for the theoretical figure.
     
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